Fix update_depot_tools for git checkout

Fix update_depot_tools for git checkout

Otherwise, the output was:
  fatal: Needed a single revision
  invalid upstream origin

R=szager@chromium.org
BUG=
TEST=


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=147064

[cmp, 2012-07-17 19:01:22]

lgtm

2 things: szager is OOO this week, other thing is I added this code, so I should
probably take a look at the change.

What branches do you have in your depot_tools checkout?  Do you have multiple
'origin' upstreams?  The update_depot_tools script still works for me as it is
before this CL.  I would assume it will still work for me after you land this
CL, too.  Just wondering how your depot_tools is different.

[M-A Ruel, 2012-07-17 19:03:41]

On 2012/07/17 19:01:22, cmp wrote:
> lgtm
> 
> 2 things: szager is OOO this week, other thing is I added this code, so I
should
> probably take a look at the change.
> 
> What branches do you have in your depot_tools checkout?  Do you have multiple
> 'origin' upstreams?  The update_depot_tools script still works for me as it is
> before this CL.  I would assume it will still work for me after you land this
> CL, too.  Just wondering how your depot_tools is different.

cygwin, git --version: 1.7.9
msysgit git --version: git version 1.7.10.msysgit.1

Both fail. Looks like an issue with git >  1.7.4.

[cmp, 2012-07-17 19:06:08]

On 2012/07/17 19:03:41, Marc-Antoine Ruel wrote:
> cygwin, git --version: 1.7.9
> msysgit git --version: git version 1.7.10.msysgit.1
> 
> Both fail. Looks like an issue with git >  1.7.4.

sh$ git --version
git version 1.7.7.3
sh$ ./update_depot_tools
sh$ echo $?
0

So it sounds like you expected that to fail where it succeeded?

[M-A Ruel, 2012-07-17 19:09:12]

On 2012/07/17 19:06:08, cmp wrote:
> On 2012/07/17 19:03:41, Marc-Antoine Ruel wrote:
> > cygwin, git --version: 1.7.9
> > msysgit git --version: git version 1.7.10.msysgit.1
> > 
> > Both fail. Looks like an issue with git >  1.7.4.
> 
> sh$ git --version
> git version 1.7.7.3
> sh$ ./update_depot_tools
> sh$ echo $?
> 0
> 
> So it sounds like you expected that to fail where it succeeded?

That's weird. Here's my ubuntu 11.04 host:

(M=9aa1c tests/) ~/src/b/depot_tools> ./update_depot_tools
Unpacking objects: 100% (4/4), done.
fatal: Needed a single revision
invalid upstream origin
(M↓=9aa1c tests/) ~/src/b/depot_tools> git --version
git version 1.7.4.1

Note that git-svn was configured on it.

[cmp, 2012-07-17 19:13:11]

It would be good to understand why in one environment it works while it fails
elsewhere.  However, if you're confident that this CL fixes the broken cases
you're seeing and doesn't break any working cases (eg. mine :) ), then go for
it!

[M-A Ruel, 2012-07-17 19:20:54]

On 2012/07/17 19:13:11, cmp wrote:
> It would be good to understand why in one environment it works while it fails
> elsewhere.  However, if you're confident that this CL fixes the broken cases
> you're seeing and doesn't break any working cases (eg. mine :) ), then go for
> it!

It could related to the way upstream is setup. I'm really not sure why it work
only for some people. In any case, using the actual branch name will help.

[commit-bot: I haz the power, 2012-07-17 19:21:03]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/maruel@chromium.org/10784045/1

[commit-bot: I haz the power, 2012-07-17 19:23:40]

Change committed as 147064